21520534515 has 16 divisors (see below), whose sum is σ = 36458317728. Its totient is φ = 10802464256.

The previous prime is 21520534501. The next prime is 21520534531. The reversal of 21520534515 is 51543502512.

It is a cyclic number.

It is not a de Polignac number, because 21520534515 - 2⁹ = 21520534003 is a prime.

It is a super-2 number, since 2×21520534515² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 42196872 + ... + 42197381.

It is an arithmetic number, because the mean of its divisors is an integer number (2278644858).

Almost surely, 2^21520534515 is an apocalyptic number.

21520534515 is a deficient number, since it is larger than the sum of its proper divisors (14937783213).

21520534515 is a wasteful number, since it uses less digits than its factorization.

21520534515 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84394278.

The product of its (nonzero) digits is 30000, while the sum is 33.

The spelling of 21520534515 in words is "twenty-one billion, five hundred twenty million, five hundred thirty-four thousand, five hundred fifteen".